Great news! Still plugging along with repairs with your welder powered by recycled 650A/CCA AGM. A great score. It replaced a Sunnko 799. An unfortunate China welder experience, for me, while others fared well.

On my the bench that monster AGM is no problem. I keep it and a battery conditioner on 24/7/365. All good, no Lipo sweat.

Mine has been going strong for years (10's of thousands of welds). Switched to a more flexible car audio power cable which makes it a bit nicer to use.
Using 3S Sinopoly 100Ah LiFePO4 cells, quite degraded from use in a car, but works VERY well.

Anyone weld any Boston Power Swing cells using this welder? If so what settings and material did you use? (.015, .030 nickel, .010, .005 copper)?? I am trying to build 14s5p battery packs for my kids electric scooters. I have 4 cases of these cells and have heard they are very difficult to spot weld. Thanks for your time..

I started using my welder and it seems I’m getting some weak welds... and they get a little stronger if I rotate the copper leads. Is my battery not strong enough? 530ca 425cca reserve capacity 75 (whatever that means) using .15 nickel at 26ms

If I get a stronger battery would it help? Or do I have to clean/sand the tips of the copper. I know I’m doing something wrong somewhere

I started using my welder and it seems I’m getting some weak welds... and they get a little stronger if I rotate the copper leads. Is my battery not strong enough? 530ca 425cca reserve capacity 75 (whatever that means) using .15 nickel at 26ms

If I get a stronger battery would it help? Or do I have to clean/sand the tips of the copper. I know I’m doing something wrong somewhere

I bought it certified/used from autozone. It currently reads 12.94 volts and it’s been off the trickle charger for 2 days. I’m gonna try and return it for a bigger one today. This may be the issue.
What size battery are you using?

I also have a optima 1000 ca / 800cca battery in my old GTO is that to strong for this?

I started using my welder and it seems I’m getting some weak welds... and they get a little stronger if I rotate the copper leads. Is my battery not strong enough? 530ca 425cca reserve capacity 75 (whatever that means) using .15 nickel at 26ms

If I get a stronger battery would it help? Or do I have to clean/sand the tips of the copper. I know I’m doing something wrong somewhere

Dont use too much pressure on the tips! 750CCA is good enough for 0,2mm

wait what? i kind of press down pretty hard on them this way the nickle strip is touching the cells very solid. is that wrong?

Yes, the key is to press so you get a good contact but you cannot press too hard. If you do, your welds will be weak - you need to have some resistance to make the actual weld, this is from my experience with this thing. BIG contact area =weak welds. This is why you get better welds if you turn the leads - probably because they are sharper there=small contact area. This could of course be compensated with more pulse current from the battery.

1. You can use standard 12V ac/dc adapter with 5.5/2.1 mm barrel connector (most common one), 500 mA is fine, maybe even less, but I haven' tried. It's polarity will be marked, it's standard negative outer, and inner pin is positive. There is a diode on the input so nothing will happen if you accidentally reverse polarity.

1. You can use standard 12V ac/dc adapter with 5.5/2.1 mm barrel connector (most common one), 500 mA is fine, maybe even less, but I haven' tried. It's polarity will be marked, it's standard negative outer, and inner pin is positive. There is a diode on the input so nothing will happen if you accidentally reverse polarity.

hello friend.
Could I replace the battery with a modified microwave transformer?

The welder circuit won't work with AC. If you had a rectifier on the output of the transformer, it could possibly work but the rectifier would need to handle over 1000 amps. I don't think a transformer would be able to supply enough current to make good welds even if you could find a big enough rectifier.